Process of forming thread



y 1953 c. F. GRAM 2,639,214

PROCESS OF FORMING THREAD Filed Aug. :5, 1945 2 Sheets-Sheet 1 Fig. 2.E1; 5.

INVENTOR." CARL F GRAN May 19, 1953 c. F. GRAM 2,639,214

PROCESS OF FORMING THREAD Filed Aug. 3, 1945 2 Sheets-Sheet 2 INVENTOR.CARL E QHAM [#4 we y Patented May 19, 1953 PROCESS OF FORMING. THREADGarl F. Grama-Bbwaytcn, Conn;, assignor-t'o-North American Rayon;Gorporation, New York N. 36., a corporation: of Delaware ApplicationAugust3, 1945,.S'erialNo. 608555 L Claim 1? In the-productionof hightenacity rayon yarn such as is employed in the production of heavy dutytires used on aircraft, trucks, guncarriages and" the'like where severeservice conditions are encountered, many important factors'enter intothe method" of treating the yarn; One'of thesefactorsisthe rapidity withwhich'impur-itiescon-- tained in-such yarn, as-a result ofitsformation,can be removed from theindividual' filaments of which the yarn-iscomposed:

High tenacity viscose yarn, for example, is ordinarily producedbyextruding-- a Viscose spinningsolution into 'an-acid spin bathunderconditionstoform a thread; withdrawing the-thread thus'formedfromthebath before complete re-' generation-citric cellulose contentofthe-viscose has been completed, passing the incompletely regeneratedthread:through a hot water'bath under stretching to accelerateregeneration; and then collecting: it on a -per-forated bobbin uponwhi-ch: complete'regeneration of the cellulose takes-place anctupon:which it-is: subsequently subjected toi after-treatment such as-washingto remove acidti and desulphurizing to: removessulphur. therefrom.Eurther after treatmenti may include additional was-hing, bleaching,sizing and: like steps. com.- monly; practiced; in the rayon. and.allied textile: arts;

Onetfeaturecof great? importance in the preserc. vation; of. the tensilestrength of; suchi-ya-rn-v is the prompt andioomplete remoualzofthe acidas soon as regenerationbathe/cellulose attained: sub;-

stantial completion so as to avoid acidattack'on,

the cellulose andi'consequent degeneration thereof. In after-treatingpackages of such synthetic thread much; difficulty has: been'aexperienced in securing adequate penctrationoftheatter-treating liquidsinto the layers of yarn so that it sometimes occurs that completetreatment of the packages' required such a long period of time thatacid" degradation of" the yarn was; experienced, While such acondition-can in'some small meassure be tolerated-in yarn-of ordinarycommercial quality having less than 100- filaments, the-com;- pleteremoval of impuritiesfrom each portionof each'filament' as'rapidly aspossible becomes'of paramount importance where the utmost strength of;every'filament is depended upon, as in the production of, fabric "forheavy duty tires," etc;

In the ordinary production of synthetic, yarn by the stretch" spinningmethod the bundle of filaments forming the yarn assume a parallelarrangement and lie substantially in one plane thus forming a flatribbon like yarn strand. Prior art teaches (see British Patent No.297,063) that 2 liquid penetration of a yarn? package is better effectedwhen the filaments composing the yarn are twisted; I have? discoveredthat it is not the twistingbut the" arrangement ofthe filaments in theform of a circular cylindrical bundle, rather than in a flat ribbon likestrand, that effects-better penetration of after-treating liquidinto-the yarn package; United States Patents Nos;

1,492,316 and"2,036,174" both disclosemea-n's for at least partiallytwisting a yarn' either during or preparatory to liquid treatment.So'far'as I am'- aware however there is" no prior art which combinesshaping a' yarn strand with" the stretching of the filaments of which"the strand" is composed and immediately packagingthe'yarn' for after--treatment.

The primary object of this'invention is to re duce to a minimumthe-timerequired adequately to remove-the impurities fromfreshly'spunsyn thetic yarn having at least loofilamentsz Anotherobject" is wanna-re the washing; out" of the acid as soonas'regenerationof thecellulose content-ofthe yarn' is completed.

A furtherobject isto so orient the filaments" of a yarnstrandimmediately'be'fore its collectionthat' eaclrportiorrof the strandretainsasubstan'- tially circular" cylindrical cross section" sothatwhen the strandis cross-wound on'a perforated, bobbinin a plurality oflayers it ftn'ms' apackage which is-readily pervious" to after-treatingfluids.

The above-and other objects may be' attained? by employing thisinvention which embodies among its features; a guide roller having; aplurality of spaced: flanges, the said guide roller being at an angle toandop'eratin'g'in conjunc' tion with a godetwheel around both of. whichthe yarn on its way} from its source of origin to its point ofcollectionis given a'numberofhelical turns in such a manner'that' itrides th'eflanges and is thereby given a slight rolling movement Fig. 2is a front view of a godet wheel and a guide roller assembly as employedin connection with this invention,

Fig. 3 is a side view of Fig. 2, and

Fig. 4 is a fragmentary sectional view through a thread package embodyinthis invention.

Referring to the drawings in detail a spinning machine designatedgenerally l includes a spinning trough l I containing a coagulant intowhich a. spinning solution is introduced through a spinning pump withcandle filter I2 and goose neck l3 which terminates beneath the surfaceof the coagulant in a spinnerette (not shown). Mounted above thespinnerette on a substantially horizontal axis is a godet wheel andguide roller I4 and [5 respectively about which the thread l6, formed bycontact of the spinning solution with the coagulant, is wound for a fewturns in the form of a helix. Mounted adjacent and coextending parallelwith the trough II is a trough I'l containing a hot aqueous liquidhaving a temperature above 60 0., preferably hot water,

beneath the surface of which is disposed a guide roller (not shown)about which the thread upon leaving the godet and guide roller l4 and I5is guided.

From the guide roller, which is immersed in the hot, aqueous liquid, thethread passes upwardly to a second godet wheel l8 which operates about ahorizontal axis at a somewhat higher peripheral speed than the godetwheel I4 so as to impart stretch to thread as it passes through said hotliquid. Mounted adjacent the godet wheel [8 on an axis of about 14 tothe horizontal is a guide roller [9 having formed in its periphery aplurality of spaced grooves in which the thread is laid in the form of ahelix. As shown in Fig. 3 the thread entering the grooves rides theflanges as it traverses the godet wheel [8 and guide roller 20, and thefilaments forming the thread are thus condensed and manipulated so as toform a strand which is substantially circular in cross-section.

Leaving the godet wheel l8 and guide roller I9, the thread thus formedinto a strand of circular cross-section passes downwardly beneath agrooved guide roller 2| and thence upwardly through a traverse mechanism22 to a collecting bobbin 23 upon which the strand is cross-wound in apackage 24 ready for further treatment.

Due to the circular cross-section of the thread strand the thread layersin the package 24 form interstices 25 (Fig, 4) through which treatingfluids readily can pass, and hence the acid and impurities contained inthe thread can be removed before any deleterious effects areexperienced.

Actual tests have shown that thread packages produced under ordinaryconditions in which the thread strand assumed a fiat ribbon like form,possessed a perviousness which would allow them to pass only about sixand one-half liters of liquid per hour whereas like bobbins wound underlike conditions except that the thread strand was so shaped as to becircular in cross-section possessed a perviousness which enabled them topass over forty liters of liquid per hour. Tests made on bobbins woundwith 1100 denier high strength yarn containing 480 filaments inaccordance with this invention, show substantially complete acid removalwith standard pressure vacuum washing equipment in a period of fifteenminutes whereas like tests made on bobbins wound with like yarn inaccordance with the conventional practice and washed as recited above,show at the end of a sixty minute washing period an acid content of overfifty percent of that initially contained in the package. As aconsequence, by employing this invention the high strength imparted tothe yarn due to the stretching and hot water treatments can be preservedand the acid and impurities can be flushed out of the yarn package assoon as regeneration is completed.

While in the foregoing there has been shown and described the preferredembodiment of this invention, it is to be understood that minor changesin the details of construction, combination and arrangement of parts maybe resorted to without departing from the spirit and scope of theinvention as claimed. The term high-tenacity rayon yarn denotes yarnspun from viscose, cuprammonium cellulose, viscose-casein solutions,etc. having at least 2 grams dry strength per denier,

I claim:

In the method of producing high tenacity rayon yarn wherein a spinningsolution is extruded into a spin bath under conditions to form amultifilament yarn strand, the resultant strand being then directedthrough a hot aqueous liquid, sub jected to stretch, and finallycollected on a perforated bobbin in the form of a cross-wound takeuppackage ready for after-treatment, the improvement comprising the stepsof forming said multifilament strand in a spin bath of relatively lowtemperature, withdrawing the strand as fast as formed from the bath bymeans of a first godet and roller unit before complete regeneration hasset in, then passing said strand through an aqueous bath ofsubstantially higher temperature to accelerate regeneration thereof,withdrawing it therefrom by means of a second godet and roller unitdriven at a slightly higher peripheral speed than said first unit toimpart stretch to said strand, and, while stretching said strand andwhile the regeneration thereof is continuing in accelerated fashion,abruptly changing the path of said strand a plurality of times for ashort distance of travel and in such angular directions during itspassage over said second godet as to impart a rolling motion thereto andcause it to acquire a lasting, substantially circular cylindrical shapeand collectin said circular strand into a cross-wound package having amultitude of interstices.

CARL F. GRAM.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date Re. 22,178 Oppenlaender Sept. 15, 1942 1,820,621 Junkers Aug.25, 1931 1,966,487 De Long July 17, 1934 1,968,912 Schrenk Aug. 7, 19342,074,022 Oppenlaender Mar. 16, 1937 2,110,926 Williams Mar, 15, 19382,303,274 Herrstrom et al. Nov. 24, 1942 2,317,747 Ewing Apr. 27, 19432,325,127 Gladding July 27, 1943 2,369,190 Thurmond Feb. 13, 19452,370,180 McCrosky Feb. 27, 1945 2,439.829 Tippetts Apr, 20, 1948

